The present invention relates to printing an electronic document subject to usage rights.
With the growing demand for online content, providers of distributed electronic content, such as publishers, distributors, and Web retailers, often desire to restrict access to the content to authorized users only. For example, a copyright holder may wish to restrict access to those individuals who have paid for a copy of an electronic book.
Some electronic content is distributed in a freely-readable form, that is, with no protection against unauthorized use or copying. Other content is distributed in encrypted or otherwise protected form. For example, encrypted documents require a decryption key or other mechanism for rendering the document readable to an authorized user. Some decryption mechanisms use the same encrypted document and same key for all users. Others produce a specifically-encrypted document and unique key for each user. Yet others use the same encrypted document for all users, but supply a separate decryption, or usage rights file, that is unique to each user and is in some way tied to the user or the user""s computing environment.
Prior usage rights designs allow a document provider to set access permissions so that only two printing alternatives are permittedxe2x80x94i.e., xe2x80x9cno printingxe2x80x9d and xe2x80x9cprintingxe2x80x9d. If printing is allowed, the operation produces a high-fidelity original of the document. For example, an encrypted document printed to an Adobe(copyright) PostScript(copyright) printer can result in a PostScript file stored on disk. This PostScript file is a complete, high-fidelity, unencrypted (i.e., plaintext) version of the document and can be used to republish the encrypted original. This is undesirable from a copyright-protection standpoint, as the high-fidelity original can be mass distributed, and the source document can be recovered from the printout by OCR (optical character recognition) processing or from a page description language print file.
In general, in one aspect, the invention provides a method and an apparatus including a computer program product for printing an electronic document. The method includes receiving an electronic document and usage rights, the usage rights permitting uses of the document including a low-fidelity print use; rendering the document in response to a print request by creating a low-fidelity bitmap for each page of the document in accordance with the usage rights; and printing the low-fidelity bitmaps to an output device, whereby the print output is a low fidelity rendering of the document. Advantageous implementations can include one or more of the following features. The document is rendered at a pre-determined resolution specified in the usage rights. The document is rendered at a resolution lower than a minimum required by an optical character recognition (OCR) system. The document is rendered at a pre-determined color fidelity specified in the usage rights. The document is rendered at a color fidelity of 2-bit grayscale. The print output is produced on a piece of paper, on film, or on a display screen.
Advantages that can be seen in implementations of the invention include one or more of the following. The invention provides a document provider a middle-ground choice between all-or-nothing printing operations. The invention allows a user to print a low-fidelity rendering of the electronic document that does not represent a high-fidelity original of the document. This allows the user to have a hardcopy of the document, while protecting the document provider from mass distribution of a high-fidelity original of the document. Valuable features of electronic content, such as the ability to search text, bookmarks, hyperlinks, and scalable fonts are stripped out in the low-fidelity bitmaps.
The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features and advantages of the invention will become apparent from the description, the drawings, and the claims.